Method of end lasting



' Jan. 31,196]

J. S. KAMBORIAN METHOD OF END LASTING Filed July 9, 1958 H F i.

United States PatentO METHOD or END LASTING Jacob S. Kamborian, WestNewton, Mass. International Shoe Machine Corp., 292 Main St., Cambridge,Mass.)

Filed July 9, 1958, Ser. No. 747,443

5 Claims. (Cl. 12-145) This invention relates to the lasting offootwear, more especially to end lasting, and is especially directed toa method of end lasting in which adhesive is employed to, attach themargin of an upper to an insole.

The customary way of end lasting with adhesive is to stress the upperheightwise of the last bottom in a toe lasting machine of the typeshown, for example in Patent No. 2,668,967, wipe the margin inwardly toconform the upper to the shoulder, partially retract the wipers withoutreleasing the upper, fold the margin back, that is, outwardly, daubadhesive on the margin of the folded back upper with a brush and thenwipe the upper inwardly against the bottom. In Patent No. 2,614,527,there is shown a container provided with a nozzle for use with a lastingmachine of the foregoing kind, to apply adhesive to the area of theinsole at the toe, the nozzle being shaped to fit the area andcontaining a U-shaped orifice, so arranged as to distribute the adhesiveuniformly over the surface at the toe. Another way of applying theadhesive,

is to use a spray gun or similar device for atomizing the adhesive andto spray it forcibly against the exposed margin. Such methods haveproved unsuccessful, either because not enough adhesive was applied inthe first place or if enough was applied it was squeezed out during thelasting process so that not enough remained to hold the lasting marginagainst the retractive stresses of the upper. As a consequence the bondhas not been strong enough or tenacious enough to withstand the efiectsof time, temperature and pressure incident to the subsequent operationsof drying, pounding, leveling and roughing in making the bottom readyfor the sole attaching operation and wear.

It is the primary purpose of this invention to provide a novel method ofattaching the lasting margin, at the end of a shoe, exclusively withthermoplastic adhesive, in such fashion as to produce a permanent bondwhich will hold the uplasting stress and hence snugness and sharpness ofthe upper at the shoulder of the last, which will endure throughout theroughing, pounding and bottom cementing operations subsequent thereto,which will not require for its formation any more time than is used inordinary lasting practice, which will not fail by creep throughout thelife of the shoe at ordinary temperatures and pressures expected to beencountered both in shoe manufacturing and during wear, which will notrequire any more than ordinary skill in its practice and which will notadd to the expense of the manufacturing process as a whole.

As herein illustrated, the method of end lasting comprises assemblinganinsole and upper on a last, preliminary uplasting the upper so as tostress the lasting margin perpendicular to the bottom, holding the upperunder stress at the shoulder of the last, folding the marginal edgeoutwardly, while thus held, to expose the junction between the innersurface of the upper and the insole, laying a continuous uniform ribbonof hot thermoplastic adhesive entirely around the endproximate to thejunction and then wiping the entire margin inwardly against the bottomunder a pressure perpendicular to the 2,969,555 Patented Jan. 31, 1961ice bottom. In accordance with good shoe making practice after theinitial upwipin-g stresses have been applied and before the margin isturned outwardly the margin is wiped inwardly over the bottom to conformthe upper to the shoulder, the pulling over tacks are removed, ifupstanding, and then after the margin is turned outwardly the excessmarginal material, if any, including the box toe and lining material, ifthe latter is used, is trimmed. The final wiping of the lasting marginagainst the bottom is accomplished with one or more passes of the wiper.It is desirable to apply the adhesive in the form of an extruded ribbonof round cross-section, having a diameter in the order of about aviscosity of 150 poises at a temperature in the order of 120 to 134 C.and a melting point in the order of to C.

The invention will now be described in greater detail with reference tothe accompanying drawing wherein:

Fig. 1 is a perspective of a last with an insole andupper assembledthereon, temporarily attached thereto by tacks;

Fig. 2 is a vertical section through an apparatus for conditioning thetoe prior to lasting;

Fig. 3 is a fragmentary plan view at the toe showing the wipersembracing the shoulder of the last just below the surface of the insole,with the lasting margin folded back and with a continuous ribbon ofadhesive applied along the angle between the margin and the insole;

Fig. 4 is a fragmentary vertical section to much larger scale showingthe ribbon of adhesive in cross-section as applied in the angle betweenthe lasting margin and the insole and in dotted lines its change ofshape as the lasting margin is laid down against the insole;

'Fig. 5 is a plan view of the completely lasted end;

Fig. 6 is an elevation diagrammatically showing the toe support andwipers of a lasting machine and an.

Referring to the drawing, there is shown in Fig. La 1 last 10, arrangedbottom side up with an insole 12 attached to the bottom and an upper 14pulled over the last and temporarily attached thereto, with its lastingmargin extending upwardly beyond the bottom of the last, by means of aplurality of appropr ately placed pulling over tacks 16. 'lhe assembledbottoms and uppers, as shown in Fig. 1, are prepared ahead of time andracked for the toe laster. Before commencing the lasting operationseveral assemblies are placed in a steam box 18, as shown in Fig. 2, orother suitable means for conditioning the upper material and when asuitable time has elapsed they are removed one at a time from theconditioning apparatus and lasted on a toe lasting machine of the typeshown, for example in my Patent No. 2,668,967, modified for simplicityof control, as shown in the pending application of Thomas A. Weisz,Control for Lasting Machine, Serial I No. 563,270, filed February 3,1956, now Patent No. 2,888,693, granted June 2, 1959. When properlylocated in the aforesaid machine with the toe resting on the toe support(Fig. 6), the wipers 20 may be manipulated in conjunction with thesupport to apply an updrafting, he'ightwise stress to the uppermaterial, substantially perpendicular to. the bottom. By repeatedmanipulation of the wipers and support the upper material may be drawntaut and smooth over the last to eliminate all wrinkles and the lastingmargin m caused to stand upwardly from the bottom. When the upper hasbeen suitably stressed heightwise of the bottom the wipers aremanipulated to move inwardly, parallel to the bottom, and in contacttherewith, so as to fold the lasting margin over the shoulescapee,

der and downwardly against the bottom while holding it under stress. Asa preliminary to the inwiping operation the pulling over tacks at thetoe may be removed and after several manipulations have been performedto draw the upper in to the satisfaction of the operator, the wipersare, partially withdrawn, but without releasing the upper. As partiallywithheld they bear only against the upper at the shoulder, just belowthe plane of the bottom of the insole and thus hold the upper understress while leaving the upstanding lasting margin free to be foldedoutwardly, as shown in Fig. 3-, to expose the angle between the innersurface of the lasting margin and the edge of the insole. At this timeif there is an excess of lasting margin, lining and/or counter materialthe excess may be trimmed oif. With the upper material folded back acontinuous ribbon of adhesive24"substantially smaller in itscross-sectional dimensions than the height of the lasting margin In isapplied directly'in the angle which is represented at a in Fig. 4,around the entire end of the shoe. The wiping should, be carried out asquickly as possible after applying the adhesive. V

The "ribbon of adhesive may be extruded from a nozzle 26 f(Fi'g."6)"into the angle, the nozzle being connected to a pot 28,vvhich isprovided with heating means for liquifying the adhesive as it isrequired and which, together with the nozzle, is inountedon an arm 30,swingable on a suitable support 32 mounted on the frame of the toelaster for movement in .a horizontal plane. The nozzle itselfisfpref'e'rably mounted on a flexible conductor so thatit may bemanipulated by the operator to follow the angle closely throughoutchanges in radius of. the end. By using'a slender "nozzle, asillustrated, no heat is transmitted to, thefinsole o'rjupp'er,consequently there is very little danger that the. adhesive, after. ithas been applied, will be kept soft and hence squeezeout. asthe marginis wiped ih va ridly hy'thefvv'ipers: i

n: lieu 'ofasiiigle'noizle andto effe' :t a moreuniformtemper'aturecondition in 'the applied ribbon of adhesive be actuated tomove from a spread apart position toward a common point or vice versa,as shown, to apply two symmetrically disposed ribbons starting at thetip and diverging rearwardl'y or starting at the sides and convergingforwardly. The nozzles may be pivotally supported at the lower end of asuitable conductor 3-4, for supplying adhesive ito'the'r'n and haveactuating links 36 connected to a commoni handle or other operatinglever. 'to effect their pivotal'muvement; V i

It may be desirable to usefa crescent shaped nozzle 40, as shown in Fig;8,"havin g a narrow discharge slot 42 for applyingthe ribbon of adhesivethroughout the entire length, from one 'side around the tip to the otherside. The nozzle may be supplied at one or more points with adhesivethroughconductors 44 and a suitable check valve willbe employed to cutoff a'finite ribbon as it is extruded. A thin narrow nozzle is employedso that it can be advanced close tothe'edge without touching the insoleand hence without transferring heat thereto. Nozzles of dif feren't sizewill be made available, each of which is designed'to-beusefulfor shoesof two or three consecutive s1zes;

Followingdisposition of the ribbon of adhesive in the angle the wipers20, are again moved inwardly over the bottomso as to lay the lastingmargin downagainst the bottom-andto press it into intimate contacttherewith. One or two passes of the wiper sufiice, whereupon, the lastedshoe maybe immediately removed without any waiting period-forsetting ofthe adhesive bond.

To be effective, *as distinguished from prior practice, wherein theadhesive was applied with a brush or by spraying, the adhesive must beapplied as a continuous ribbon around the'entire toe orheel which isbeing lasted directlyin the angle between the intersection of the innersurface .of theupper and the upper surface of the-insole at the veryedge. Preferably the ribbon should be of generally circularcross-section and have a diameter in the order of 55, although it is tobe understood that efiective bonding can be obtained over a range of $4to ,6 If less than ,4, there is an insufiicient surface covering toproduce the desired bond, and if more than 1 much of it is squeezed outby pressure of the wipers so as to be objectionable. In Fig. 4 thedisposition of the ribbon of adhesive is shown greatly enlarged withrespect to the parts of the shoe and in dotted lines there is shown whatis believed to take place as the margin is laid down. The followingaction is predicated upon using a thermoplastic adhesive having a rathernarrow range of liquid solid transition. In other words, the adhesivestays solid up to and within a very few degrees of its melting point andconversely solidifies very quickly upon cooling a few degrees from itsmelting point. Consequently, there is substantially no softening periodand no chance for the adhesive bond to distort if held for a sufficientlength of time to permit its solidification. adhesive it is possible toapply it at a temperature close enough to its solidifying point so thatthe parts of the shoe to which it is applied immediately brings theadhesive down to a solidifying point, at least on its surface, within afew seconds after it touches the parts, thus forming a bond between thesurface of the adhesive and the parts being joined which holds some ofthe adhesive in the corner, as shown in Fig. 4. As the wipers arebrought inwardly however the still hot interior part of the adhesion.ribbon is squeezed away from the corner and caused to roll forwardlybetween the closing angle, spreading over the surfaces as they cometogether and adhering thereto because itv solidifies as fast as it comesin contact therewith, with very little danger of being squeezed out frombetweenv the interfaces ashas happened previously due to heating of theinsole during the application of the l adhesive-. v

Thus, by controlling the quantity and temperature of the adhesive, usinga thermoplastic adhesive having a very narrow range of solid to liquidphase, and starting its application at the corner so that it has a longpath to cover before it reaches the edge of the margin, it is possibleto. produce a bond between the lasting margin and the insole which takeseffect progressively as the lasting margin .is'laid down so that by thetime the margin is fully laid down the bond is sufliciently strong toresist the retractive forces in the upper material. Accordingly,

the completed. shoe may be removed from the lasting machine at oncewithout fear of the upper pulling back because of weakness .in the bondor fear of gradual creep or flow of the adhesive itself over a period oftime so as to release the margin. 7

The following are three examples of adhesive of a character required toafford a satisfactory bond according to the method of lasting describedabove.

Viscosity. 15.0.poisesatIZIP C.

By choosing such an The resins referred to in the foregoing examples areidentified as follows:

Chemical Oomposition Resin Source Polyamide of dimerized vegetable oilfatty acid and polyamine.

Pentaerythritol ester of wood rosin.

Low molecular Weight polymer of styrene or its homologues.

(1) Versarnid 930 General Mills, Inc

rln

Hercules Powder Co- (2) Versamid 9 (3) Versamld (4) Pentalyn A (5)Piecolastic A25 Pennsylvania Industrial Chemical Corp.

The completely lasted end of a shoe is shown in Fig. 5, and has beenfound to be so permanent in its character that it does not lose itsefiectiveness or allow the upper to lose its snugness even while thebottom is being hammered, leveled and subjected to roughing preparatoryto attaching the outsole to the bottom.

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modificationsand equivalents which fall within the scope of the appended claims.

I claim:

1. The method of lasting shoes wherein the upper and insole have beenassembled on a last with a lasting margin at one end of the shoeextending upwardly from the insole, comprising, depositing a ribbon ofadhesive proximate to the juncture of the margin and insole whichissubstantially smaller in its cross-sectional dimensions than the heightof the lasting margin and wiping the lasting margin over the insole sothat portions of the ribbon will travel from proximate to the junctureoutwardly thereof between the insole and lasting margin and otherportions of the ribbon will progressively be caused to adhere to themargin and the insole during this travel.

2. The method of lasting shoes wherein the upper and insole have beenassembled on a last with a lasting margin at one end of the shoeextending upwardly from the insole, comprising, depositing a ribbon ofadhesive proximate to the juncture of the margin and insole which issubstantially smaller in its cross-sectional dimensions than the heightof the lasting margin and wiping the lasting margin over the insole sothat portions of the ribbon will be squeezed in the direction of thelasting stress ahead of the approaching surfaces of the margin andinsole as they are brought together while leaving other portions of theribbon adhering to the surfaces which have been brought into contact.

3. The method of lasting shoes wherein the upper and insole have beenassembled on a last with a lasting margin at one end of the shoeextending upwardly from the insole, comprising, depositing a ribbon ofadhesive proximate to the juncture of the margin and insole which issubstantially smaller in-its cross-sectional dimensions than the heightof the lasting margin and wiping the lasting margin over the insole sothat as the ribbon is squeezed portions of it will roll along ahead ofthe lasting margin as successive portions of the margin are pressed intoengagement with the insole, while other portions of the ribbon willremain adhering to the surfaces which have previously been brought intoengagement.

4. The method of lasting shoes wherein the upper and insole have beenassembled on a last with a lasting margin at one end of the shoeextending upwardly from the insole, comprising, depositing a ribbon ofadhesive proximate to the juncture of the margin and insole which issubstantially smaller in its cross-sectional dimensions than the heightof the lasting margin but which contains enough adhesive per unit lengthto afford an adequate amount of adhesive for bonding the entire width ofthe margin to the insole without excess, and wiping the lasting margininwardly over the insole and the ribbon resting thereon, so that theribbon is caused to roll from proximate to the edge of the insoleinwardly, leaving as it rolls layers of adhesive on the margin andinsole which adhere thereto and to each other so as to bond the marginto the insole.

5. The method of lasting shoes wherein the upper and insole have beenassembled on a last with a lasting margin at one end of the shoeextending upwardly from the insole, comprising depositing a continuousribbon of liquid thermoplastic adhesive smaller in its cross-sectionaldimensions than the height of the lasting margin and having a narrowliquid to solid temperature range, proximate to the juncture of thelasting margin and insole at said end, the adhesive solidifying at leaston its surface when deposited, and wiping the lasting margin over theinsole so that portions of the ribbon will travel from proximate to thejuncture outwardly thereof between the insole and lasting margin andother portions of the ribbon will progressively be caused to adhere tothe insole and lasting margin during this travel.

References Cited in the file of this patent UNITED STATES PATENTS855,868 Thoma June 4, 1907 1,989,607 Ray Jan. 29, 1935 2,055,483 EngelSept. 29, 1936 2,614,527 Karnborian Oct. 21, 1952 2,728,737 WittcotfDec. 27, 1955 2,742,142 Paulsen Apr. 17, 1956 FOREIGN PATENTS 15,649Great Britain of 1911 777,957 Great Britain July 3, 1957

